river_dict = {}
river_dict['尼罗河'] = '非洲'
river_dict['黄河'] = '亚洲'
river_dict['亚马逊河'] = '美洲'

for river_name, river_address in river_dict.items():
    print(f"{river_name}流经{river_address}")

for river_name in river_dict.keys():
    print(river_name)

for river_address in river_dict.values():
    print(river_address)